next remove the header pipe. the bolts are 12mm on the head and where the muffler attaches in the rear under the shock. The stock pipe will also have a bolt under the right foot rest that will need to be removed.

remove the plastic cover to gain better access to the three throttle body bolts. Use a 10mm ratcheting wrench to remove the three bolts.
Next loosen the clamp and move the throttle body out of the way. Set the brown spacer aside.

Remove the connectors for the injector and throttle position sensor.
note: if you have an MSX 125 you will also have an idle air control valve.

It is not necessary to remove the fuel line unless you want it off and out of the way, but it is easy to do. If you do remove it push in on the white clip and slide in the clip in toward the line. This will allow you to slide it off and remove the fuel line.